Fuel control apparatus



y 9 1950 L. A. WILLIAMS, JR

FUEL CONTROL APPARATUS 2 Sheets-Sheet 1 Filed Feb. (28, 1947 J W JM y31950 L. A. WILLIAMS, JR 2,507,130

FUEL CONTROL APPARATUS Filed Feb. 28, 1947 2 Sheets-Sheet 2 3 s3 s4 4 M3 Ti i m if: A

j 5 74 I 56 g 56 54 I I W Patented May 9, 1950 2,507,130JEUELLQONTROLARBARAIUS LynniA.-Williams,-Jr., Indianzpoligslndlgassignor :tO-SteWarflWar-nerCorporatiomfihicagm,Ill., a he corporationon-Virginia Application iEelutuary 28;"1947; Serial ND; 731,474

l1 *1 (-Jlaim. Ol.-1236e;-e68) My invention relates generally toyfuel'control apparatus, particularly apparatus for controlling the flow e f'fluid fuel to a heater.

7 Certain aspects of the present invention-have a more generalapplication andiinay beconsid r ,ered as relating to a remotelycontrolledauto- .matic pressure, I regulator: I The present" applica--tion is ,a continuation in part 0f. .y copending application SerialNo:*591;543 filed; May '2,--'1945, for" Fuel control apparatus,noW'Patent' N0; I2,483374'1,datedoctoberifij, 1.9.49.

' For the purpose of better, understanding oithe invention it will be,described as applied to a gasoline. burning automobile heater although,as

pointed out above; the inyention has zotherfutilit'yi In fluid fuel"burning heaters aslllsed for example for heating; the passengercompartments of. automobiles, the vfuel ,isj supplied from the en- In.heater's'of this typegitis comquired to heat it to atemperature atwhichit s. will ignite the fuel, and if. the fuel .is supplied to theheaterhdurin this time...interval, some 'OTfJthe fu l may passthroughthe heater-without being burned, ,or ithmay. collect in variouspart ofthe heater; Furthermore, the presence of ,thefuel in the heater.while the igniter' islbeing heated to its ignition temperature, slows.down the heating of lthe igniterabecaiise some ortheheat generatedthereby is lost in uaporizinglthe iiuel prior to the time thattheligniter is hot enough to ignite the .It is 'thereforelone of; theobjects of the'inven- .tion to provideahimproved fuel control valve for.heaters, in which the opening of thefuel supply valve isj'delayed untilthei'gniter has been heated te a'temperature at whichit can ignitethefuel.

.Afurther Object of th invention is to prov d an. improved 7electrically controlled fuel valve.

A f urther object is toprovidea fuel line valve which operatestoregulate'the pressure at which U htheifuel is, suppliedland also iselectrically pper- .ated to permit and stop the flow of fuel.

- Other objects "will: appear from the'following description, reference'being had to ,the accompanying drawings, in, which:

""Fig. l is aschematiciwiring diagram of the control circuits.andpdiagrammatically illustrates the control elementsyparts of theheater being shown'in'phantom;

2 -'-Fig="'2 is:a-centralwerticalsectionalview o'f the mprovedcontrolvalve takenonthe-line-2-2 of *Fig. 3; and

1 -Fige- 3 is-a sectional:view taken on the l-ine 3 -3 of -Fig. 2.

Referring to Fig. 1, a heater I0 is illustrated in *phantomas'comprising 'acasing I2- in which is r l0cateda-- heat-- exchanger l 4anda combustion ---chamber I5 fmm whichthe'productsot combusi tion==flow-through-the heatexchanger andare-discharged threugh an=exhausteonduitI82 Fuel is supplied to the-combustionchamber 16 through -a-'pipezufromasuitable sourcewsuch as the'fuel pumpofan automobile. Theflow-of-fuel through ithe pipe Ellis-controlledby- 'a fuel valve22;while :air for-combustion is supplied to the-combustion chamloerthrough a conduit 24.

An 'electricali'gniter"2-6 orthe hot wire-type is --suitably-located toignite the fuel-mixture in the combustion chamber and has-one of itsterminals igrounded;j*-Theother terminal is adapted to be "connected toasource of electrical'energy'such as ti the automobile {battery28-,'-t;hrough' zit-thermostatic ignite!" de-energ-izing switch; 30, ar-thermostatic 9 overheat switch" 32,- and a manually -operable heatercontrolmain switch 34.

Located in the-passenger compartment 'of the :auto'mobile or-other spaceto beheated-'byirthe "heater is a control switclr' 36-comprisinganinsulating support 38-ifor a-=thermostatie--bimetal switch arm 4 I the"free *end of which carries one of a; set of contactsv 39,?rTheother'contact inthe set is secured to theend 'of anadjustment screw 42,also supported byithe, insulatingsupport' 38. -aig"-Thus, by rotatingthe adjustment; screw 62-:the j point, atg-which-thecontacts=3e-engageigmay be "adjusted.

The switcharm 4} has aheating coil- 44 wound thereonbutinsulatedtherefrom: -Azheatingv coil '46 i's similarlywound about oneleg of a U-shaped 1 bimetallic thermostatic iactuator 43 formingpart "oftheifuel valve 22? One terminal"ofthe heating coil-46 is grounded whilethe other-terminal is connectedbyrawire 41 to the'switch-arm ll-and 3bytway of-this arm to one of *the'contacts of, the set 39: The heatingcoil id has one'of theterminalsconnected to the blade or ar'mM while'theother terminal grounded?" {The circuit-to, the battery-'28 is completedby wayof a -wire49-which leads from"thejadjustmentscrew42 to ithBiCOh---nection between the overheat switch :and the igniter; switch. Currentis therefore supplied from the battery :28 ,through the. master switch3i and overheat switch" 32 andwire; 49 tothe ad- 55 justable contactcarried bythe'screw 42? For a 26 and also to the two heating coils 44and 46. 2a

In other words, the heating coil 44 is energized through the contacts 39while the heating coil 46 is energized by way of these same contacts,the resistance in this direction being considerably lower than by way ofthe resistor 51 with the result that very little current flows throughthe latter resistor. As the temperature of the bimetal blade til risesit will deflect downwardly and separate the contacts 39, therebyde-energizing the circuit through the heater coil 44 and reducing thecurrent flow through the heater 46, the latter heater being suppliedonly by way of the relatively high resistance 51. Subsequently the bladeM will cool sufficiently to reengage the contacts 39, thereby repeatingthe cycle.

The fuel valve 22 is preferably of the construction illustrated in Figs.2 and 3, and comprises a body 56 having the fuel supply pipe 2iconnected thereto to supply fuel through an inlet port 52. A valve seatmember 54 is threaded in the body 56 and is provided with a valve seat56 and a port 58. Within the valve seat member 54 there is a cylindricalbore providing a guide for a valve stem 66, which is of noncircularcross section to provide a passageway 62 for the flow of fuel. A valvedisc 64 is secured to the valve stem 68 by a shouldered pin 66 pressedinto the stem. The stem is recessed to receive a helical coil spring 68which rests upon an apertured centering seat '58 and normally holds thevalve disc 64 in engagement with its seat 56.

A flexible diaphragm 52 has its edge clamped between the body 22 and aplate 14 by a plurality of cap screws '16. The diaphragm 12 has acentral opening which is closed by a member 18, the latter beingsuitably clamped to the diaphragm in a fuel-tight manner. The member i8has a bore for the reception of a compression coil sprin 80, the upperturn of which is of reduced diameter and has a ball bearing 82 silversoldered or brazed thereto. The U-shaped bimetal 48 is symmetrical andhas one end of one leg SI thereof fastened to the plate 74 by screws 15.The other leg 83 of this U-shaped bimetal which has the electricalheating winding 46 thereon, has its end located directly above the ball82 so as normally to be in contact therewith. The leg 81 flexes inresponse to ambient temperature and thus acts as an ambient temperaturecompensator for the leg 83. The U- shaped bimetal is protected by a thinsheet metal cover 84 and the space enclosed by this cover has freeaccess to the atmosphere through a hole 86 formed in the plate 14. Theflow through the pipe 26 will be restricted by a small orifice in a wellknown manner.

In operation, the main switch 34 is closed by the operator of thevehicle, thus supplying current through the normally closed overheatswitch 38, the heater winding 44, switch 36, and heater winding 46. Inaddition, current will be supplied to the igniter '26 through theigniter deenergizing switch 30 and to the heater 48 by way of thebridging resistor As the leg 83 of the U-shaped bimetal 48 is heated,its free end presses downwardly upon the diaphragm through the spring80, and after it has been heated for a length of time suflicient for theigniter 26 to have attained ignition temperature, will exert asufiicient force in a downward direction upon the pin 86 to move thevalve disc 64 from its seat 56. Fuel may therefore fiow past the valveinto the chamber beneath the diaphragm i2, exerting pressure thereonopposin that applied by the leg 83. At the same time, the bimetal switcharm 4! will be heated and will commence flexing downwardly so that thecontacts 39 will soon be separated, thereby de-energizing heater 44 andreducing the current flow through heater 46. The contacts 39subsequently reclose after a short time interval.

As soon as the fuel commences flowing to the heater past the valve 64,it will be ignited by the igniter and ventilating air flowing throughthe casing l2 will commence delivering heat to the space to be heated.As the combustion heater approaches its normal operating temperature,the igniter de-energizing switch 39 will open, thereby turning off theigniter.

Because of the heat capacity of the bimetal blade at there will be anappreciable time interval after current starts flowing through theheating element 46 before the bimetal blade 48 will respond suificientlyto open the valve 22. During this time interval the igniter 26 is raisedsubstantially to ignition temperature so that by the time the fuelreaches the heater in any substantial quantity the igniter wil1 be hot.

The bridging resistor 5| is provided so that if the circuit to theheater system is closed at the switch 34 sufficient current will alwaysflow through the heating element 46 to insure operation of the heater atthe minimum level. In other words, if the temperature within the spaceto be heated is high enough so that the contacts 39 remain disengagedthe heater nevertheless will receive sufficient fuel to operate. Thisprevents the possibility of fuel being supplied at a rate too low tomaintain combustion.

As the pressure of the fuel within the chamber beneath the diaphragmbuilds up, the pressure which is exerted on the diaphragm 12 by the fuelwill tend to cause the valve 64 to move toward closed position, suchmovement being permitted but resisted by the spring 86 and theresiliency of the U-shaped bimetal 48.

Due to the time constant of the cycle imposed by the time required toheat and cool the bimetal switch arm ll, fuel will be continuouslysupplied to the heater, but the average rate at which it flows willdepend upon the relative length of time that the switch 36 is closed andopened. This is caused by the fact that when the switch is closed for alonger interval, the leg Si will be heated to a higher temperature andtherefore will deflect downwardly to a greater extent and cause the fuelin the chamber below the diaphragm 12 to attain a higher pressure, andthus an increased flow rate. The length of the portion of the cycleduring which the switch 36 is closed is, of course, determined by thetemperature of the air in the space being heated and the setting of theadjustment screw 42.

The remotely controlled pressure regulator valve is quite smooth in itsoperation. In other words, the pressure on the downstream side of thevalve will remain substantially constant over a period of time withoutsubstantial fluctuations because the impulse sending unit has acomparatively short cycle of operation while the receiving unit has aheating element 44 and blade 48 with a considerably longer period ofoperation. As an example, if the sending unit sends impulses at the rateof one every three or four seconds or so and the rate of response of thereceiving unit is such that these impulses are integrated smoothly so asto cause the receivin bimetal blade to have a smooth downward or upwardtrend until a balanced condition is reached it will be appreciated thatthe abrupt on and off cycles of the sending unit will have littleinstantaneous effect on the receiving unit. The effect, therefore, isthat an increased demand for heat will result in greater powerdissipation in the heater coil 44 over a period of time, thereby causingthe bimetal blade 48 gradually to apply a higher and higher pressure tothe end of the valve stem 6'0. The result is that a higher and higherfuel pressure will be required in the space beneath the diaphragm T2 tobalance the pressure conditions set up by the bimetal actuating blade48.

Whenever the heater switch 34 is opened the system will be de-energizedwith the result that the heating element 46 and bimetal blade 48 willcool. Pressure is therefore relieved upon the valve stem 66 and thevalve is closed by the spring 69, thereby turning off the supply of fuelto the heater until such time as the switch 34 is reclosed.

As is customary in heaters of this type, the igniter de-energizingswitch 3!] recloses upon sufilcient cooling of the heater, due tofailure of combustion, while the overheat switch 32 will be openedwhenever the normal operating temperature of the heater is materiallyexceeded.

It will thus be clear from the foregoing that the control systemoperates in an efficient and reliable manner to control the pressure atwhich fuel is supplied to the heater, and that this control means is notonly responsive to the temperature of the space being heated, but alsohas provisions to prevent opening of the fuel supply valve until acertain time sufilcient for the igniter to attain ignition temperaturehas elapsed.

While I have shown and described a preferred embodiment of my invention,it will be apparent that numerous variations and modifications thereofmay be made without departing from the underlying principles of theinvention. I therefore desire, by the following claim, to include withinthe scope of the invention all such variations and modifications bywhich substantially the results of my invention may be obtained throughthe use of substantially the same or equivalent means.

I claim:

A fuel shutoif and modulating control valve for combustion heaters ofthe type which include an electric igniter of incandescent type which isslow to heat to ignition temperatures when energized. said valvecomprising a valve body having a valve seat therein and having achamber, in-

let and outlet passages in said body connected to said chamber, saidinlet passage including said valve seat, a valve co-operaole with saidseat, a diaphragm forming one wall of the chamber 1 and connected toapply a valve closin force to said valve which is a function of thepressure in said chamber, resilient means urging said valve against saidseat, a thermostatic element, a resilient operating connection betweensaid thermostatic element and said valve, an electric heater to heatsaid thermostatic element to cause the latter to apply a force throughsaid resilient operating connection in a direction to open said valve,said force being a function of the electric energy dissipated in saidelectric heater, the characteristics of said thermostatic element, saidelectrical heating means and said resilient means being such thatsimultaneous energization of said heating means and said igniter willresult in said igniter heating to ignition temperature before the forceapplied by said thermostatic element is suflicient to open said valve,circuit means including a source of electric energy for application ofan electric potential to said electric heater to vary the force imposedupon said valve by said thermostatic element, and a thermostatic circuitinterrupter in said circuit to determine the proportion of the time saidpotential is applied to said electric heater in accordance with thetemperature of said thermostatic circuit interrupter, said thermostaticcircuit interrupter being sensitive to the temperature of the space tobe heated by said combustion heater.

LYNN A. WILLIAMS, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,974,884 Spencer Feb. 20, 19341,994,771 Knopp Mar. 19, 1935 2,143,277 McCorkle Jan. 10, 1939 2,229,402Anderson Jan. 21, 1941

